init client base structure

Signed-off-by: Marko Kungla <marko.kungla@gmail.com>

.editorconfig

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+# Editor config helps developers define and maintain consistent
+# coding styles between different editors and IDEs
+# EditorConfig is awesome: http://editorconfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.gitattributes

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+# https://git-scm.com/docs/gitattributes
+#
+# A gitattributes file is a simple text file that gives attributes to path names
+# Each line in gitattributes file is of form: pattern attr1 attr2 ...
+# That is, a pattern followed by an attributes list, separated by white spaces.
+# When the pattern matches the path in question, the attributes listed on the
+# line are given to the path. Each attribute can be in one of these states for a
+# given path:
+
+################################################################################
+# DEFAULTS
+################################################################################
+* text=auto
+* eol=lf
+
+################################################################################
+# TEXT:
+# Ensure that the following files, and file name patterns are treated correctly
+################################################################################
+.editorconfig text
+.gitattributes text
+.gitignore text
+.md text
+LICENSE text
+*.yml text
+*.yaml text
+

.gitignore

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+################################################################################
+# GITIGNORE
+# repository is place for source code not for binaries if you need to include
+# binaries in repository then consider appropriate values .gitattributes
+################################################################################
+
+################################################################################
+# FILES to ignore
+################################################################################
+*~
+**/*.sw[mnop]
+################################################################################
+# DIRECTORIES to ignore
+################################################################################
+
+################################################################################
+# exception rules
+################################################################################
+!**/*.gitkeep
+!**/*go.mod
+!**/*README.md

.golangci.yaml

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+# options for analysis running
+run:
+  # default concurrency is a available CPU number
+  # concurrency: 4
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  timeout: 1m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+  # list of build tags, all linters use it. Default is empty list.
+  # build-tags:
+  #   - mytag
+
+  # which dirs to skip: issues from them won't be reported;
+  # can use regexp here: generated.*, regexp is applied on full path;
+  # default value is empty list, but default dirs are skipped independently
+  # from this option's value (see skip-dirs-use-default).
+  # "/" will be replaced by current OS file path separator to properly work
+  # on Windows.
+  # skip-dirs:
+  #   - pkg/log
+
+  # default is true. Enables skipping of directories:
+  #   vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
+  skip-dirs-use-default: true
+
+  # which files to skip: they will be analyzed, but issues from them
+  # won't be reported. Default value is empty list, but there is
+  # no need to include all autogenerated files, we confidently recognize
+  # autogenerated files. If it's not please let us know.
+  # "/" will be replaced by current OS file path separator to properly work
+  # on Windows.
+  # skip-files:
+  #   - ".*\\.my\\.go$"
+  #   - lib/bad.go
+
+  # by default isn't set. If set we pass it to "go list -mod={option}". From "go help modules":
+  # If invoked with -mod=readonly, the go command is disallowed from the implicit
+  # automatic updating of go.mod described above. Instead, it fails when any changes
+  # to go.mod are needed. This setting is most useful to check that go.mod does
+  # not need updates, such as in a continuous integration and testing system.
+  # If invoked with -mod=vendor, the go command assumes that the vendor
+  # directory holds the correct copies of dependencies and ignores
+  # the dependency descriptions in go.mod.
+  modules-download-mode: readonly
+
+  # Allow multiple parallel golangci-lint instances running.
+  # If false (default) - golangci-lint acquires file lock on start.
+  allow-parallel-runners: false
+
+# output configuration options
+output:
+  # colored-line-number|line-number|json|tab|checkstyle|code-climate|junit-xml|github-actions
+  # default is "colored-line-number"
+  format: colored-line-number
+
+  # print lines of code with issue, default is true
+  print-issued-lines: true
+
+  # print linter name in the end of issue text, default is true
+  print-linter-name: true
+
+  # make issues output unique by line, default is true
+  uniq-by-line: true
+
+  # add a prefix to the output file references; default is no prefix
+  path-prefix: ""
+
+  # sorts results by: filepath, line and column
+  sort-results: true
+
+issues:
+  # Independently from option `exclude` we use default exclude patterns,
+  # it can be disabled by this option. To list all
+  # excluded by default patterns execute `golangci-lint run --help`.
+  # Default value for this option is true.
+  exclude-use-default: true
+  # Fix found issues (if it's supported by the linter)
+  fix: false
+  # Excluding configuration per-path, per-linter, per-text and per-source
+  exclude-rules:
+    # Exclude some linters from running on tests files.
+    - path: _test\.go
+      linters:
+        - gocyclo
+        - errcheck
+        - dupl
+        - gosec
+    # Exclude lll issues for long lines with go:generate
+    - linters:
+        - lll
+      source: "^//go:generate "
+    - linters:
+        - lll
+      source: "^# "
+severity:
+  # Default value is empty string.
+  # Set the default severity for issues. If severity rules are defined and the issues
+  # do not match or no severity is provided to the rule this will be the default
+  # severity applied. Severities should match the supported severity names of the
+  # selected out format.
+  # - Code climate: https://docs.codeclimate.com/docs/issues#issue-severity
+  # -   Checkstyle: https://checkstyle.sourceforge.io/property_types.html#severity
+  # -       Github: https://help.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-an-error-message
+  # default-severity: error
+
+linters:
+  disable-all: true
+  enable:
+    # Enabled By Default Linters
+    - deadcode
+    - errcheck
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - typecheck
+    - unused
+    - varcheck
+    # Disabled By Default Linters
+    - asciicheck
+    - bodyclose
+    - cyclop
+    - depguard
+    - dogsled
+    - dupl
+    - durationcheck
+    - errorlint
+    - exhaustive
+    - exhaustivestruct
+    - exportloopref
+    - forbidigo
+    - forcetypeassert
+    - funlen
+    - gochecknoglobals
+    - gochecknoinits
+    - gocognit
+    - goconst
+    - gocritic
+    - gocyclo
+    - godot
+    - godox
+    - goerr113
+    - gofmt
+    # - gofumpt
+    - gci # run it after gofumpt
+    - goheader
+    # - goimports
+    # - gomnd
+    - gosec
+    - ifshort
+    - lll
+    - makezero
+    - misspell
+    - nakedret
+    - nestif
+    - nilerr
+    - nolintlint
+    - prealloc
+    - predeclared
+    - revive
+    # - nlreturn
+    - stylecheck
+    - unconvert
+    - unparam
+    - wastedassign
+    - whitespace
+
+linters-settings:
+  cyclop:
+    # the maximal code complexity to report
+    max-complexity: 15
+
+  exhaustivestruct:
+    # Struct Patterns is list of expressions to match struct packages and names
+    # The struct packages have the form example.com/package.ExampleStruct
+    # The matching patterns can use matching syntax from https://pkg.go.dev/path#Match
+    # If this list is empty, all structs are tested.
+    struct-patterns:
+      - "*.Test"
+  funlen:
+    lines: 80
+    statements: 40
+
+  gci:
+    # put imports beginning with prefix after 3rd-party packages;
+    # only support one prefix
+    # if not set, use goimports.local-prefixes
+    local-prefixes: github.com/howijd/
+  goconst:
+    ignore-calls: true
+    ignore-tests: false
+
+  goheader:
+    values:
+      const:
+        AUTHOR: The Howijd.Network Authors
+    template: |-
+      Copyright {{ YEAR }} {{ AUTHOR }}
+      SPDX-License-Identifier: Apache-2.0
+
+      Licensed under the Apache License, Version 2.0 (the "License");
+      you may not use this file except in compliance with the License.
+      You may obtain a copy of the License at:
+
+        http://www.apache.org/licenses/LICENSE-2.0
+        or LICENSE file in repository root.
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+      See the License for the specific language governing permissions and
+      limitations under the License.

client.go

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+// Copyright 2022 The Howijd.Network Authors
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//   or LICENSE file in repository root.
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package koios
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// GET sends api http get request to provided relative path with query params
+// and returns an HTTP response. When using these methods you are wxpected
+// to handle the response according to net/http.Do documentation.
+// e.g. Caller should close resp.Body when done reading from it.
+func (c *Client) GET(ctx context.Context, path string, query ...url.Values) (*http.Response, error) {
+	return c.request(ctx, "GET", nil, path, query...)
+}
+
+func (c *Client) request(
+	ctx context.Context,
+	m string,
+	body io.Reader,
+	p string,
+	query ...url.Values) (*http.Response, error) {
+	var (
+		requrl *url.URL
+	)
+
+	p = strings.TrimLeft(p, "/")
+	c.mux.RLock()
+	switch len(query) {
+	case 0:
+		requrl = c.url.ResolveReference(&url.URL{Path: p})
+	case 1:
+		requrl = c.url.ResolveReference(&url.URL{Path: p, RawQuery: query[0].Encode()})
+	default:
+		c.mux.RUnlock()
+		return nil, fmt.Errorf("%w: got %d", ErrURLValuesLenght, len(query))
+	}
+	c.mux.RUnlock()
+
+	// optain lock to update last ts and total
+	// request count. Lock will block is another request is already queued.
+	// e.g. in other go routine.
+	c.mux.Lock()
+
+	// handle rate limit
+	for !c.lastRequest.IsZero() && time.Since(c.lastRequest) < c.reqInterval {
+	}
+
+	c.lastRequest = time.Now()
+	c.totalReq++
+
+	// Release client so that other requests can use it.
+	c.mux.Unlock()
+
+	req, err := http.NewRequestWithContext(ctx, strings.ToUpper(m), requrl.String(), body)
+	if err != nil {
+		return nil, err
+	}
+
+	return c.client.Do(req)
+}
+
+func (c *Client) BaseURL() string {
+	c.mux.RLock()
+	defer c.mux.RUnlock()
+	return c.url.String()
+}
+
+func (c *Client) TotalRequests() uint {
+	c.mux.RLock()
+	defer c.mux.RUnlock()
+	return c.totalReq
+}
+
+func (c *Client) updateBaseURL() error {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+	raw := fmt.Sprintf("%s://%s", c.schema, c.host)
+	if c.port != 80 && c.port != 443 {
+		raw = fmt.Sprintf("%s:%d", raw, c.port)
+	}
+	raw += "/api/" + c.version + "/"
+	u, err := url.ParseRequestURI(raw)
+	if err != nil {
+		return err
+	}
+	c.url = u
+	return nil
+}